Hi! You can say that the way you put it. But if you say like this, it might sounds a little more natural to Japanese ears. Still your guess is so close though! 「これは（この食べ物は）アメリカ人の口にあいますね。」and for the 2nd one, sure, you can say that:) another a little more polite way to say that is this:「お口に合う分かりませんが、お召し上がり頂けると光栄（嬉しい）です。」(often used when you are presenting a package of gifts in person or with an attachment note with it) Hope this helps to clear your questions out a bit.